In combustion engines, intake manifolds provide air or air/fuel mixtures to cylinders. A throttle body coupled to an intake manifold at a first end may control the manifold pressure and flow delivered to the cylinders. The flow from the throttle body enters a plenum, which in turn directs the flow to a plurality of runners in fluidic communication with intake ports of the cylinders. In addition, intake manifolds are designed to reduce noise, vibration, and harshness (NVH) generated by the flow.
U.S. Pat. App. No. 2010/0326395 describes an intake manifold cover with braces integral to its exterior, provided to enhance the structure of the cover and reduce NVH. The braces extend upwardly and outwardly from brace flange portions which themselves extend outwardly from the intake manifold and are disposed between adjacent intake runner ports. The braces are integrally formed with the cover.
Although the above described braces are integrally formed with the intake manifold, their inclusion may increase the weight, cost, and complexity in forming the intake manifold beyond acceptable targets. Further, the inventors herein have recognized an interdependency between the noise/vibration generated by the manifold, and noise/vibration generated by flow passing by the throttle and entering the manifold. For example, certain actions taken to increase stiffness may exacerbate noise generated by flow past the throttle.
Systems for reducing NVH associated with an inlet in an intake manifold while reducing added weight, cost, and complexity are provided.
In one example, an intake manifold may include one or more runners and a plenum fluidically coupled to the one or more runners. The intake manifold may include an inlet having a wall thickness, a first indentation protruding radially inward at a first inflection point in a first direction, and a second indentation protruding radially inward at a second inflection point in a second direction substantially anti-parallel to the first direction. The wall thickness may be maintained at the first and second inflection points.
In this way, by including indentations in an intake manifold inlet flow passage, NVH associated with the intake manifold and its inlet may be reduced. Further, the intake manifold may provide and withstand sufficient pressures while minimizing resistance at its inlet, and maintain a sufficient seal with the throttle body and other components, without increasing wall thickness, weight, cost, or complexity. Further still, such an approach can work synergistically with approaches that reduce throttle flow noise, such as vanes positioned at the throttle inlet, while still maintaining weight, wall thickness, and other requirements.
In another example, a system is provided comprising a throttle body and an intake manifold coupled to the throttle body. The intake manifold may have one or more runners fluidically coupled to a plenum, a plurality of ribs extending along an exterior surface, and a top shell and a bottom shell oppositely joined together to thereby form the intake manifold. The inlet may have a double-humped cross-section with a first indentation and a second indentation, the first and second indentations extending radially inward at a first inflection point and a second inflection point, respectively. Ribs of the plurality of ribs may have a greater length at the first and second inflection points. The one or more runners may not have the double-humped cross-section.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
FIGS. 2-7 are drawn approximately to scale, although other relative dimensions may be used, if desired.